|Publication number||US6896498 B1|
|Application number||US 10/819,421|
|Publication date||May 24, 2005|
|Filing date||Apr 7, 2004|
|Priority date||Apr 7, 2004|
|Also published as||CN1680720A, CN100441873C|
|Publication number||10819421, 819421, US 6896498 B1, US 6896498B1, US-B1-6896498, US6896498 B1, US6896498B1|
|Inventors||Tapesh P. Patel|
|Original Assignee||Scroll Technologies|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (6), Referenced by (4), Classifications (15), Legal Events (3)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This application relates to a scroll compressor having a protection device that releases the back pressure chamber refrigerant if an oil temperature reaches an undesirably high level. The present invention thus better addresses certain operational problems more quickly than the prior art.
Scroll compressors are becoming widely utilized in refrigerant compression applications. In a scroll compressor, a pair of scroll members each include a base and a generally spiral wrap extending from the bases. The wraps interfit to define compression chambers. One of the two scroll members is caused to orbit relative to the other, and as the two orbit, the size of the compression chambers is reduced, compressing an entrapped refrigerant. As the refrigerant pressure increases, a separating force from the refrigerant tends to force the two scroll members away from each other. Thus, scroll compressor designers tap a portion of a compressed refrigerant to a chamber behind the base of one of the two scroll members. This is called a “back pressure chamber” and serves to bias the two scroll members together, resisting the separating.
Various operational challenges exist with the scroll compressor. In particular, the complex surfaces between the two scroll members present a good deal of interfitting contact surfaces. Under certain conditions, there can be damage along the contact surfaces. As an example, if the motor for the scroll compressor is improperly wired, the compressor could run in a reverse direction. This will cause unduly high temperatures to quickly exist in the scroll compressor. This can lead to various damage to the compressor components. As an example, there can be galling of the base plates and the wraps.
Further, another problem can exist due to the cooling method utilized in most sealed compressors. In most sealed compressors, suction refrigerant is passed over the motor resulting in cooling of the motor. However, under certain conditions, the charge of refrigerant in the system may be unduly low. This is known as a loss of charge situation. When there is a low amount of suction refrigerant moving over the motor, the motor may not be adequately cooled.
Thus, there are protection devices for these adverse situations. In one traditional scheme, a motor protector is placed on the motor and includes a temperature sensor. The temperature sensor trips to open a circuit, and stop further operation of the motor should the temperature sensor sense an unduly high temperature. These basic motor protectors have been placed in various locations within the scroll compressor.
Another method that is utilized in combination with these motor protectors is to bring the heat from the scroll compressor pump unit, which will typically become hot more quickly than other areas in the scroll compressor under adverse conditions, to the motor protector. As an example, one prior art arrangement has a valve that opens when an unduly high temperature is sensed in the discharge refrigerant. The valve will pass refrigerant from the compression chambers down into the suction chamber that surrounds the motor and hence the protector. Another method passes hot oil onto the motor protector, again to trip the motor protector temperature sensor more quickly than if the motor protector temperature sensor simply was reacting to the temperature in the motor chamber.
While the above-described protection methods provide benefit, it would be desirable to have an initial protection occur before the extreme temperature that now results in the tripping of the motor. To date, the known scroll compressors have not adequately provided more prompt relief of the adverse conditions.
In the disclosed embodiment of this invention, hot oil is returned over a valve that sits in a passage communicating the back pressure chamber to the suction chamber surrounding the motor. Should the hot oil temperature reach an unduly hot temperature, the valve opens. With the valve open, the back pressure refrigerant passes through the passage, into the suction chamber, and onto the motor protector. This will more quickly trip the motor protector than is the case in the prior art.
Preferably, that same oil also drips onto the motor protector. In addition, by opening the back pressure chamber, the scroll members will be allowed to move away from each other, and will more readily resist the problems with galling, undue tip thrust, etc. mentioned above.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.
A scroll compressor 20 is illustrated in
A first scroll member 30, known as an orbiting scroll, includes a spiral wrap 32 extending from a base 34. The illustrated scroll wrap is of a so-called “hybrid” style having varying thickness in its scroll wraps. Other types of scroll compressors would come within the scope of this invention, including a scroll wrap formed on an involute of a circle, which would have a relatively constant thickness to its wraps. The orbiting scroll 30 faces a non-orbiting scroll 36 having a base 38 in its own wrap 40 extending from the base. As shown, the wraps interfit to define compression chambers 41. The drive shaft 25 is driven to rotate, and a non-rotation coupling causes the orbiting scroll 30 to orbit relative to the non-orbiting scroll 36, as known.
Certain challenges are raised by the operation of such scroll compressors. In particular, it sometimes occurs that the motors are mis-wired, such that they are driven in a reverse direction. When this occurs, the temperature of the refrigerant can reach unduly high levels, and there can be damage to the scroll members. In particular, the surfaces between the tips and the opposed base can result in galling, unduly high tip pressure, etc. All of this would be undesirable from a base 34. The orbiting scroll 30 faces a non-orbiting scroll 36 having a base 38 in its own wrap 40 extending from the base. As shown, the wraps interfit to define compression chambers 41. The drive shaft 25 is driven to rotate, and a non-rotation coupling causes the orbiting scroll 30 to orbit relative to the non-orbiting scroll 36, as known.
Certain challenges are raised by the operation of such scroll compressors. In particular, it sometimes occurs that the motors are mis-wired, such that they are driven in a reverse direction. When this occurs, the temperature of the refrigerant can reach unduly high levels, and there can be damage to the scroll members. In particular, the contact at surfaces between the tips and the opposed base can result in galling, unduly high tip pressure, etc. All of this would be undesirable.
Another challenge is when there is an insufficient charge of refrigerant in the refrigerant cycle. In particular, the refrigerant leading into the suction chamber 28 must be of a sufficient volume to cool motor 24, or motor 24 can reach unduly high temperatures. When there is a loss of charge on the refrigerant line supplying the refrigerant to the suction tube 26, there may be insufficient refrigerant to adequately cool the motor.
As is known, a separating force is created in the compression chambers 41 tending to move the orbiting scroll 30 away from the non-orbiting scroll 36. Thus, to address this, a back pressure chamber 42 is provided behind the base of one of the scroll members. The back pressure chamber 42 is illustrated behind the base of the orbiting scroll 30, however, it should be understood that other scroll compressor designs incorporate a back pressure chamber behind the non-orbiting scroll, and would benefit from this invention also. An inner seal 46 and an outer seal 48 define the back pressure chamber 42. The compressed refrigerant from the compression chamber 41 passes through the tap 44 and into the back pressure chamber 42. This tapped compressed refrigerant forces the orbiting and non-orbiting scrolls together.
As shown in the figure, an oil supply line 49 supplies oil from a sump at the bottom of the housing 22 upwardly through the drive shaft 25. The oil is directed to various operational surfaces. Some of the oil is returned through an oil return line 50 extending through a crankcase 51. The oil from supply line 49 communicates with a bearing chamber 52 including a yoke 54 from the orbiting scroll, and a bearing 56, and to return line 50. From return line 50, the oil may flow onto motor protector 60. As can be appreciated, during the above-described adverse conditions, this oil will reach higher temperatures than would otherwise be expected.
A valve 59 is placed on a passage 58 leading to the back pressure chamber 42. The valve 59 is a thermal valve which, when exposed to unduly high temperatures, will open to dump the refrigerant from the back pressure chamber 42 into return line 50, and eventually to a motor protector 60. As known, the motor protector 60 includes a temperature-sensitive switch that opens to stop operation of the motor should unduly high temperatures be reached. By dumping the back pressure chamber from back pressure chamber 42 onto the motor protector 60, the present invention ensures that the shutting off of the motor occurs more quickly than if the hot oil were simply allowed to drip onto the motor protector 60.
As shown in
Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US4596520 *||Dec 5, 1984||Jun 24, 1986||Hitachi, Ltd.||Hermetic scroll compressor with pressure differential control means for a back-pressure chamber|
|US6077057 *||Aug 29, 1997||Jun 20, 2000||Scroll Technologies||Scroll compressor with back pressure seal protection during reverse rotation|
|US6217302 *||Feb 24, 2000||Apr 17, 2001||Scroll Technologies||Floating seal bias for reverse fun protection in scroll compressor|
|US6554592 *||Oct 16, 2001||Apr 29, 2003||Scroll Technologies||Scroll compressor with condition responsive back pressure chamber valve|
|JPH05187370A *||Title not available|
|JPS6412091A *||Title not available|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US7326039 *||Jan 14, 2005||Feb 5, 2008||Lg Electronics Inc.||Apparatus for varying capacity of scroll compressor|
|US20060099097 *||Jan 14, 2005||May 11, 2006||Lg Electronics Inc.||Apparatus for varying capacity of scroll compressor|
|US20100089093 *||Jun 8, 2009||Apr 15, 2010||Cheol-Hwan Kim||Scroll compressor and refrigerating machine having the same|
|US20120294733 *||Jan 19, 2011||Nov 22, 2012||Daikin Industries, Ltd.||Compressor|
|U.S. Classification||418/55.5, 418/57, 418/94, 418/55.4|
|International Classification||F04C28/26, F01C1/02, F04C18/02, F04C29/04, F04C18/00, F04C28/28|
|Cooperative Classification||F04C18/0215, F04C2270/19, F04C28/28, F04C28/265|
|Apr 7, 2004||AS||Assignment|
Owner name: SCROLL TECHNOLOGIES, ARKANSAS
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:PATEL, TAPESH P.;REEL/FRAME:015195/0037
Effective date: 20040325
|Oct 31, 2008||FPAY||Fee payment|
Year of fee payment: 4
|Sep 28, 2012||FPAY||Fee payment|
Year of fee payment: 8